title: Gravity affects the vertical curvature in human grasping movements.
abstract: When humans make grasping movements their digits' paths are curved vertically. In a previous study the authors found that this curvature is largely caused by the local constraints at the start and end of the movement. Here the authors examined the contribution of gravity to the part of the curvature that was not explained by the local constraints. Subjects had to grasp a tealight (small cylinder) while sitting on a chair. The authors could rotate the whole setup, including the subject, relative to gravity, whereby the positions of the starting point and of the tealight relative to the subject did not change. They found differences between the paths that are consistent with a direct effect of gravity pulling the arm downward.
authors.affiliation: MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, the Netherlands.
authors.forename: Rebekka
authors.initials: R
authors.lastname: Verheij
authors.forename: Eli
authors.initials: E
authors.lastname: Brenner
authors.forename: Jeroen B J
authors.initials: JB
authors.lastname: Smeets
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology*; D005260:Female; D006112:Gravitation; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male